Tire Talk

Tire terminology

The part of the tire which most people call the tread is technically called the crown. The tread is actually the grooves or depressions which are in the crown. Sometimes this is also called the "design" of the tire.

The tread provides traction and handling characteristics for different kinds of driving and roads such as racing, winter driving conditions, mud and off-road use, rainy or wet road driving, etc.

The Sidewall is the part between the crown and the inner edges of the tire where it is mounted on the rim of the wheel. This is where a lot of information about the tire is found.

The edge where the tire joins with the wheel is called the bead. The bead contains steel wires embedded in the rubber for strength.

There are two basic types of air-filled tires: tube type and tubeless.Tubeless are almost the only type used today on passenger cars.The tire is mounted directly on a wheel and is airtight to hold the air in the tire.

The tube type has a rubber tube (called an inner tube) which contains the air. This tube is inside the hollow opening of the tire. This kind of tire mostly is used mostly on wheels with spokes such as you find on bicycles and motorcycles.

Tubeless tires have an inner lining which can be self sealing if a minor puncture occurs, but inner tubes will begin to lose pressure with even a tiny pin prick.

Radial tires are the most commonly used today for cars. The term "radial" refers to the way the tire is constructed with reinforcing threads or cords which are embedded in the rubber running across the tire from bead to bead and allow some flexibility in the side-to-side movement of the tire for better handling.

Bias-ply or cross-ply tires have reinforcing cords which run from one side to the other at an angle. Because the angles cross this makes the tire stonger and more ridgid. This can be useful where strength is more important than handling. Cars mostly use radial tires while trucks and trailers use the bias-ply tires more frequently.

Radial

Bias Ply

Do not mix bias ply and radial tires, especially on the same axle (front or rear).

Most of the characteristics of tires which we've discussed here are marked on the sidewall of the tire which we describe at tire markings.